Fin stabilized projectile



Dec. 6, 1966 J. J. DONNELLY ETAL. 3,239,537

FIN STABILIZED PROJECTILE Filed July '7, 1965 2 Sheets-Sheet 1 INVENTORSJOHN .1. DONNELLY ANDREW d. GRANDY BY FRANCJS SHlNALY;

W) WM (QOQAW W ATTORNEYS 1966 J. J. DONNELLY ETAL 3,289,587

FIN STABILIZED PROJECTILE Filed July '7, 1965 2 Sheets-Sheet 2 INVENTORSJOHN J. DONNELLY ANDREW d. QRANVY BY FRANUS J.$H\NALY ATTORNEYS itedStates Patent Ofiice 3,289,587 Patented Dec. 6, 1956 3,289,587 FINSTABILIZED PROJECTILE John J. Donnelly, Willingboro, NJ., and Andrew J.Grandy, North Hills, and Francis J. Shinaly, Levittown, Pa, assignors tothe United States of America as represented by the Secretary of the ArmyFiled July 7, 1965, Ser. No. 470,303 Claims. (Cl. 102-49) The inventiondescribed herein may be manufactured and used by or for the Governmentfor governmental purposes without the payment to us of any royalty thereThis invention relates to propellant actuated devices and, moreparticularly, to fin stabilized projectile or rocket arrangements. Theinvention is especially directed to improved projectile constructionswhich are adapted for use in a breechless, recoilless launcher orweapon.

Among the objects of the invention are the provision of such a weaponthat is much lighter in weight than prior recoilless weapons, is simplerin construction, more accurate, and more reliable over a widetemperature range. A r'u'rther object of the invention is to provide aweapon having a more equal pressure distribution throughout itslaunching tube and particularly at the muzzle end thereof.

In one aspect of the invention a propellant actuated device is providedwhich includes a main body having a peripheral portion, fin meansconnected to the body and extending rearwardly of the body and outwardlyat least as far as the peripheral portion, the fin means havingprotuberance means thereon, and propellant means positioned forwardly ofthe protuberance means.

These and other objects, features and advantages will become apparentfrom the following description and accompanying drawings in which:

FIG. 1 is an elevational view partially broken away in section of apreferred weapon construction embodying the principles of the invention.

FIG. 2 is an enlarged sectional view of the projectile arrangement ofFIG. 1.

FIG. 3 is an elevational view of the FIG. 1 projectile in flight withits fins in their stabilizing position.

FIG. 4 is a view similar to FIG. 1 of a modified construction.

FIG. 5 is a sectional view of one of the fins taken along line 5-5 ofFIG. 4.

FIG. 6 is a rear end view of the arrangement in FIG. 4.

The breechless and recoilless weapon of FIG. 1 includes a launching orgun tube 11 having open rearward and forward ends 12, 13, each beingflared outwardly and the forward end 13 defining a muzzle portion of thetube 11.

Positioned in the tube 11 is a projectile arrangement shown generally at15 (FIGS. 1, 2) and including a main cylindrical body 16 the peripheryof which is slidable longitudinally within the launching tube. Integralwith body 16 is a transverse member or section 17 that divides the bodyinterior into a forward chamber 18 containing a high explosive material19 having a detonating means 20. The conical cavity formed by coppercone 21 and the cavity within the forward reduced portion 22 of the body16 form a stand-01f distance or spacing between the cone 21 andpreferably an electrical fuze 23. An inner, concentrically spaced sleeve24 is integrally connected with the body 16 by its annular rear wall 25to define a cylindrical piston support for piston 26 which is slidabletherein. Pivotally connected as at 28 to an appropriate rear portion ofbody 16 is a plurality of fin members 27 each having an inwardlyextending tab or protuberance portion 29 which are of an enlargedtransverse cross-sectional dimension to define a central throat ornozzle-like longitudinal passage 30. Within the cavity 31 formed by thefolded fins 27 is a consumable or frangible propellant container 32having its sidewall portions supported by the fin members 27, or in useas a free rocket container 32 is provided with sulficient strength orthe fins are provided with an initial retaining ring 27 The forwardportions of the fins 27 each have their innermost edges provided with anotch 33 (FIG. 3) or the like to normally receive laterally extendingedges of a rear disk 34 carried by the piston 26. A central passage 35through the piston places the cavity 31 in communication with theannular pressure chamber 36 in the rear portion of the body 16.

Preferably the propellant in container 32 is single-grain or multiplegrains arranged according to a predetermined geometrical configurationand is ignited by an electrical ignition means 37. The gas generated bythe propellant will develop sutficient pressure within cavity 31 andultimately chamber 36 to first create sufficient thrust at the nozzle orthroat 30 to provide the desired forward propulsion and then to move thepiston 26 rearwardly when the pressure in cavity 31 is reduced to apredetermined level relative to the pressure in chamber 36. The edges ofpiston disk 34 will pivot the fins 27 and their tabs 29 outwardly to apredetermined stabilizing or extended position (FIG. 3) where they areheld and thereby locked by expansion of snap ring 39 into groove 40 inthe internal surface of sleeve 24.

In the arrangement of FIG. 4 the open-ended launching tube 11 isappropriately grooved at to receive the rotating band 51 of projectilebody 52 which carries a nose 53 and adjacent high explosive portion 54in the cylindrical forward portion similar to the projectile of FIG. 2.The rear portion 55 of projectile 52 is tapered or reduced andterminates in a multi-apertured boom 56 that integrally connectstherewith a rear or tail fin stabilizing portion 57. Tail portion 57includes a plurality of laterally extending rigid fins 58 each of streamline contours (FIGS. 4, 5) wherein the common plane (dotted line 66)containing the maximum thickness of each fin also contains a pluralityof radially extending throat or nozzle constrictions 59 in thelongitudinal passageways between the respectively adjacent fins 58.Positioned around the boom 56 is a complementary pair of annuluspropellant sections each containing a multiplicity of elongatepropellant grains 61 within an appropriate consumable or frangiblecontainer 62. Preferably, an electrical ignition means 63 and boostercharge of black powder 64 within the boom will ignite the propellantthrough the boom apertures 65. Thus, the fins 58 pro vide a throat ornozzle arrangement for the pressure gas developed by the burningpropellant to propel the projectile body 52 forwardly and then renderstability to the projectile in flight when the propellant has beenconsumed or removed.

Various modifications, alterations or changes may be resorted to withoutdeparting from the scope of the invention as defined by the appendedclaims.

We claim:

1. A propellant actuated device comprising,

a main body having a peripheral portion,

fin means connected to said body and extending rearwardly of said bodyand outwardly substantially as much as said peripheral portion,

said fin means having means protruding from a rear portion thereof andextending inwardly of said peripheral portion for controlling exhaustingpropellant gas, and

propellant means positioned forwardly of said inwardly extendingportion.

2. The structure in accordance with claim 1 wherein said fin means haveforward portions that are pivotally connected to said body.

3. The structure of claim 2 in which there are provided means for movingrearward portions of said fin means outwardly about said pivotalconnection, to an extended position and means for maintaining said finrearward portions in said extended position.

4. The structure of claim 1 in which said propellant is enclosed in aconsumable case having a sidewall portion thereof supported by said finmeans during consumption of said propellant and case.

5. In a recoilless weapon having a launching tube, a propellant actuateddevice comprising a main body portion having a peripheral portionslidable in said tube,

fin means connected to said body and extending rear- References Cited bythe Examiner UNITED STATES PATENTS 2,801,587 8/1957 Gould 102-502,821,924 2/1958 Hansen et al 10250 3,118,376 1/1964 Bendersky 102-49 X3,196,793 7/1965 Milenkovic et al 10250 BENJAMIN BORCHELT, PrimaryExaminer. V. R. PENDEGRASS, Assistant Examiner.

1. A PROPELLANT ACTUATED DEVICE COMPRISING, A MAIN BODY HAVING A PERIPHERAL PORTION, FIN MEANS CONNECTED TO SAID BODY AND EXTENDING REARWARDLY OF SAID BODY AND OUTWARDLY SUBSTANTIALLY AS MUCH AS SAID PERIPHERAL PORTION, SAID FIN MEANS HAVING MEANS PROTRUDING FROM A REAR PORTION THEREOF AND EXTENDING INWARDLY OF SAID PERIPHERAL PORTION FOR CONTROLLING EXHAUSTING PROPELLANT GAS, AND PROPELLANT MEANS POSITIONED FORWARDLY OF SAID INWARDLY EXTENDING PORTION. 